Open Access
Table 1.
Each symbol and its meaning.
| Symbol | Meaning | Symbol | Meaning |
|---|---|---|---|
| ϕ | Porosity | ρ 0 | Air density |
| σ | Airflow resistivity | η | Air viscosity coefficient |
| α ∞ | Tortuosity | γ | Ratio of specific heats |
| Λ | Viscous characteristic length | P r | Prandtl number |
| Λ′ | Thermal characteristic length | ρ eq | Equivalent density |
| ω = 2π f | Angular frequency | K eq | Equivalent bulk modulus |
| P 0 | Atmospheric pressure | j | Imaginary unit |
| c 0 | Velocity of sound in air | α | Absorption factor |
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